Language and NLP Section 048
Semantic Search and Reranking
Search that finds the right passage even when none of the words match, and the reranking step that makes it good.
11 of 11 lessons published Three reading levels on every lesson
Lessons in order
Work top to bottom. Each lesson assumes the one above it.
- Keyword search vs semantic search
- Bi-encoders vs cross-encoders
- Reranking the top 50
- Hybrid search with reciprocal rank fusion
- How HNSW and IVF actually work
- FAISS
- Query rewriting and expansion
- Filtered vector search
- ColBERT and late interaction
- Learned sparse retrieval with SPLADE
- Building a retrieval test set for your own corpus